From: Roland Dreier Date: Mon, 28 Mar 2011 21:13:35 +0000 (-0700) Subject: Relax si_code check in rt_sigqueueinfo and rt_tgsigqueueinfo X-Git-Tag: v2.6.35.12~1 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=44736f7cc1e6fa539449f1327b6e88323e96de57;p=karo-tx-linux.git Relax si_code check in rt_sigqueueinfo and rt_tgsigqueueinfo [ upstream commit 243b422 ] Commit da48524eb206 ("Prevent rt_sigqueueinfo and rt_tgsigqueueinfo from spoofing the signal code") made the check on si_code too strict. There are several legitimate places where glibc wants to queue a negative si_code different from SI_QUEUE: - This was first noticed with glibc's aio implementation, which wants to queue a signal with si_code SI_ASYNCIO; the current kernel causes glibc's tst-aio4 test to fail because rt_sigqueueinfo() fails with EPERM. - Further examination of the glibc source shows that getaddrinfo_a() wants to use SI_ASYNCNL (which the kernel does not even define). The timer_create() fallback code wants to queue signals with SI_TIMER. As suggested by Oleg Nesterov , loosen the check to forbid only the problematic SI_TKILL case. Reported-by: Klaus Dittrich Acked-by: Julien Tinnes Signed-off-by: Andi Kleen Cc: Signed-off-by: Roland Dreier Signed-off-by: Linus Torvalds --- diff --git a/kernel/signal.c b/kernel/signal.c index cb0fff39f4e8..fdecae014340 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2412,7 +2412,7 @@ SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig, /* Not even root can pretend to send signals from the kernel. * Nor can they impersonate a kill()/tgkill(), which adds source info. */ - if (info.si_code != SI_QUEUE) { + if (info.si_code >= 0 || info.si_code == SI_TKILL) { /* We used to allow any < 0 si_code */ WARN_ON_ONCE(info.si_code < 0); return -EPERM; @@ -2432,7 +2432,7 @@ long do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info) /* Not even root can pretend to send signals from the kernel. * Nor can they impersonate a kill()/tgkill(), which adds source info. */ - if (info->si_code != SI_QUEUE) { + if (info->si_code >= 0 || info->si_code == SI_TKILL) { /* We used to allow any < 0 si_code */ WARN_ON_ONCE(info->si_code < 0); return -EPERM;